1x Forward Cannon
1x Battle Razor
5x Liberty Turret
1x Liberty Missile turret
I personally don't think you need too many of the heavy weaponry (Battle Razors/Pulse Cannons) due to the forward cannon doing most of the damage. I believe you can fire it 3 times before your energy is gone and 2 of these gunboats did take out a cruiser. The missile turret is a maybe.. I'm sure it can be switched with another Liberty Turret or BR/PC due to its energy consumption.